共查询到20条相似文献,搜索用时 31 毫秒
1.
K. Kato K. Tanaka S. Kayukawa K. Suzuki Y. Masuda T. Kimura K. Nishizawa T. Miki 《Applied Physics A: Materials Science & Processing》2007,87(4):637-640
1-μm-thick polar-axis-oriented CaBi4Ti4O15 (CBTi144) films were fabricated by control of nucleation and growth in alkoxy-derived non-crystalline layers on Pt foils.
The oxygen ambient during pre-baking impacted both the cross-sectional microstructure and the crystallographic orientation.
The 1-μm-thick film showed relatively high intensities of (100)/(010) diffraction lines in the X-ray diffraction profile and
simultaneously had a closely packed dense structure in the transmission electron microscopy cross-sectional profile. Resultantly,
the leakage current density decreased to about 7×10-8 A/cm2 at 10 V. The piezoelectric constant d33 was determined to be 260 pm/V at a maximum poling voltage of 60 V by measurements using piezoelectric force microscopy.
PACS 77.55.+f; 77.84.-s; 77.65.-j; 68.55.Jk 相似文献
2.
K. Kato K. Tanaka K. Suzuki T. Kimura K. Nishizawa T. Miki 《Applied Physics A: Materials Science & Processing》2005,80(7):1481-1484
In-plane c-axis oriented CaBi4Ti4O15 (CBTi144) films were fabricated on Pt foils using a complex metal alkoxide solution. The a/b-axis orientation of the ferroelectric films was affected by the preferred orientation of Pt foil, which is associated with the thickness. The 500 nm-thick CBTi144 films showed good ferro- and piezoelectric properties on 0.010 mm-thick Pt foils. The Pr and Ec were 26 C/cm2 and 230 kV/cm, respectively, at an applied voltage of 75 V. The d33 was characterized as 25–34 pm/V by piezoresponse force microscopy. The values enhanced compared to those of the CBTi144 thin film with random orientation. The polar-axis oriented CBTi144 films would open for novel devices as Pb-free piezoelectric materials. PACS 77.84.-s; 68.37.-d; 81.15.-z 相似文献
3.
V. N. Petrov A. B. Ustinov 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2010,4(3):395-400
The magnetic properties of the magnetite Fe3O4(110) surface have been studied by spin resolved Auger electron spectroscopy (SRAES). Experimental spin resolved Auger spectra
are presented. The results of calculation of Auger lines polarization carried out on the basis of electronic state density
are presented. Problems related to magnetic moments of bivalent (Fe2+) and trivalent (Fe3+) ions on the Fe3O4(110) surface are discussed. It is established that the deposition of a thin bismuth film on the surface results in significant
growth of polarization of iron Auger peaks, which is due to additional spin-orbit scattering of electrons by bismuth atoms. 相似文献
4.
The results of ab initio FLAPW-GGA computations of the band structure of two new layered low-temperature superconductors BaRh2P2 and BaIr2P2 (with a ThCr2Si2 tetragonal structure) are presented. As distinct from the family of the isostructural FeAs superconductors, they feature the complete replacement of the magnetic (Fe) metal by the nonmagnetic 4d (Rh) and 5d (Ir) metals. For BaRh2P2 and BaIr2P2, the energy bands, the distributions of the densities of electronic states, the Fermi surface topology, and the coefficients of the low-temperature electron specific heat and the molar Pauli paramagnetic susceptibility have been determined. An increase in T C in the BaRh2P2 (1 K) → BaIr2P2 (2.1 K) transition can assumingly be attributed to the features of their phonon subsystem. 相似文献
5.
D. Do S. S. Kim S. W. Yi J. W. Kim 《Applied Physics A: Materials Science & Processing》2009,94(3):697-701
Ferroelectric and dielectric properties of bilayered ferroelectric thin films, SrBi4Ti4O15 grown on Bi4Ti3O12, were investigated. The thin films were annealed at 700°C under oxygen atmosphere. The bilayered thin films were prepared
on a Pt(111)/Ti/SiO2/Si substrate by a chemical solution deposition method. The dielectric constant and dielectric loss of the bilayered thin
films were 645 and 0.09, respectively, at 100 kHz. The value of remnant polarization (2P
r) measured from the ferroelectric thin film capacitors was 60.5 μC/cm2 at electric field of 200 kV/cm. The remnant polarization was reduced by 22% of the initial value after 1010 switching cycles. The results showed that the ferroelectric and dielectric properties of the SrBi4Ti4O15 on Bi4Ti3O12 ferroelectric thin films were better than those of the SrBi4Ti4O15 grown on a Pt-coated Si substrate suggesting that the improved properties may be due to the different nucleation and growth
kinetics of SrBi4Ti4O15 on the c-axis-oriented Bi4Ti3O12 layer or on the Pt-coated Si substrate. 相似文献
6.
Jian-Ping Zhou Hong-Cai He Yi Zhang Chao-Yong Deng Zhan Shi Ce-Wen Nan 《Applied Physics A: Materials Science & Processing》2007,89(2):553-558
CoFe2O4 (CFO) thin film with highly (111)-preferential orientation was first deposited on the silicon substrate by a pulsed-laser
deposition, and then Pb(Zr0.52Ti0.48)O3 (PZT) layers were deposited with different oxygen pressures to form the bilayer CFO/PZT nanocomposite thin films. X-ray diffraction
showed that the PZT preferential orientation was strongly dependant on the oxygen pressure. The smooth film surface was obtained
after depositing the CFO and PZT layers. The bilayer thin films exhibit good ferromagnetic and ferroelectric properties, and
a low leakage current density of 0.004 μA/cm2 at 50 kV/cm. The leakage current density curves show loops for the electric polarized field when the electric field reverses.
PACS 77.84.Lf; 75.80+q; 81.05.Zx; 81.15.Fg 相似文献
7.
R. B. Lyubovskii S. I. Pesotskii V. I. Nizhankovskii W. Biberacher R. N. Lyubovskaya 《Journal of Experimental and Theoretical Physics》2004,98(5):1037-1039
The behavior of de Haas-van Alphen oscillations in the quasi-2D organic metal (ET)8[Hg4Cl12(C6H5Cl)2] was studied in detail. The section of the Fermi surface of this metal is a two-dimensional network of magnetic breakdown orbits. Only two frequencies, which corresponded to allowed closed orbits, FA and FMB, were detected. This is in agreement with the earlier studies of Shubnikov-de Haas oscillations in this metal. The reason for the absence of other allowed frequencies remains unclear. The angular dependences of the amplitudes of FA and FMB oscillations contain a series of “spin zeros.” An analysis of their positions led us to suggest that many-particle interactions were weakened in (ET)8[Hg4Cl12(C6H5Cl)2]. 相似文献
8.
The polycrystalline Bi8Fe6Ti3O27 compound was prepared by a high-temperature solid-state reaction technique. Preliminary structural analysis by X-ray diffraction
(XRD) confirms the formation of a single-phase compound in an orthorhombic crystal system at room temperature. The elemental
content of the compound was analyzed by EDAX microanalysis. Microstructural analysis by scanning electron microscopy (SEM)
shows that the compound has well defined grains, which are distributed uniformly throughout the surface of the pellet sample.
Detailed studies of temperature-dependent dielectric response at various frequencies show dielectric anomalies at 380, 389
and 403°C for 10 kHz, 100 kHz, and 1 MHz respectively. The hysteresis loop observed by applying an electric field of 12 kV/cm
on the poled sample with smaller remanent polarization supports the existence of ferroelectricity in this material. The value
of d33 of the compound was found to be 19 pC/N.
相似文献
9.
K. Kumar K. Ramamoorthy P. M. Koinkar R. Chandramohan K. Sankaranarayanan 《Journal of nanoparticle research》2007,9(2):331-335
A novel route to the growth of thin films of ZnAl2O4 in nano-scale order was developed and nano-thin films of ZnAl2O4 are grown. The variation of grain size with solution concentration is reported. The thin film was deposited by modified liquid-phase
deposition (LPD) technique using a novel acid based chemical reaction for the first time to ternary system. This modified
LPD is based on a novel reaction that favours the formation of nanostructures during the treatment of a precursor (here ZnO)
and a metal foil (Al) in diluted HF acid. The acid serves both as a solvent and catalyst. Usually, in wet process synthesis
of binary systems, the metal foil will act as F− ion scavenger. In this method, formation of a ternary compound as well as growth of thin film nanostructures of that compound
was achieved by the same chemical reaction at room temperature. The role of acid concentration in the nanostructure formation
is discussed. The relationship between HF concentration and grain size were also graphically enumerated. Structural, compositional
and surface morphological properties of thin films were studied using Philips, Xpert-MPD: X-ray diffractometer and Philips,
ESEM-TMP + EDAX, Nanoscope-III: AFM. The technique is a novel, simple and low cost route for the growth of nano-thin films
of ternary oxide material. 相似文献
10.
N. A. Abdullaev O. Z. Alekperov Kh. V. Aligulieva V. N. Zverev A. M. Kerimova N. T. Mamedov 《Physics of the Solid State》2016,58(9):1870-1875
A technology has been developed for the preparation of thin films of the Bi2Te2.7Se0.3 solid solution through the thermal evaporation in a vacuum using the “hot-wall” method. The high quality of the thin films thus prepared has been confirmed by the X-ray diffraction and Raman scattering data. The electron transport has been investigated over wide ranges of temperatures (1.4–300 K) and magnetic fields (up to 8 T). It has been assumed that the observed weak antilocalization is associated with the dominant contribution from the surface states of a topological insulator. The dephasing length has been estimated. 相似文献
11.
A novel approach of double hydroxide-mediated synthesis of nickel cobaltite (NiCo2O4) electro-active material by the hydrothermal method is reported. The obtained NiCo2O4 electro-active material displays the spinel cubic phase and hexagonal-like morphology. Thermogravimetry analysis confirms the thermal stability of the electrode material. The functional groups and phase formation of NiCo2O4 have been confirmed by FT-IR and Raman spectral analysis. The modified NiCo2O4 electrode exhibits the highest specific capacitance of 767.5 F g?1 at a current density of 0.5 A g?1 in 3 M KOH electrolyte and excellent cyclic stability (94 % capacitance retention after 1000 cycles at a high current density of 5 A g?1). The excellent electrochemical performance of the electrode is attributed to the hexagonal-like morphology, which contributes to the rich surface electro-active sites and easy transport pathway for the ions during the electrochemical reaction. The attractive Faradic behavior of NiCo2O4 electrode has been ascribed to the redox contribution of Ni2+/Ni3+ and Co2+/Co3+ metal species in the alkaline medium. The symmetrical two-electrode cell has been fabricated using the NiCo2O4 electro-active material with excellent electrochemical properties for supercapacitor applications. 相似文献
12.
The absorption spectrum of thin films of a new compound, K2CdI4, was studied. It was established that this compound belongs to direct-bandgap dielectrics and that its low-frequency electronic and excitonic excitations are localized in CdI 4 2? structural blocks of the crystal lattice. It was found that, in M2CdI4 compounds (M = K, Rb, Cs), the bandgap width E g grows and the spin-orbit splitting of the valence band top decreases with increasing ionic radius of the alkali metal. 相似文献
13.
T. D. Kolomiitsova K. F. Savvateev K. G. Tokhadze D. N. Shchepkin P. G. Sennikov I. A. Vel’muzhova A. D. Bulanov 《Optics and Spectroscopy》2012,112(4):563-573
IR absorption spectra of monoisotopic 28SiH4 and 76GeH4 are studied in Ar and N2 matrices at 10 K. It is shown that the absorption spectra of silane and germane are similar in the regions of the stretching
ν3 and bending ν4 vibrations. Four groups of bands can be separated out in the spectra of each molecule: (1) narrow bands characteristic of
the matrix isolation studies, (2) broad bands, (3) diffuse absorption with a large value of the spectral moment M
2* the intensity of which increases upon annealing, and (4) bands of dimers the intensity of which increases quadratically with
concentration. The spectra of 28SiH4 and 76GeH4 in nitrogen matrices contain a triplet in the stretching region and a doublet in the bending region, which is explained by
the change in the molecular symmetry from T
d
to C
3V
on passage from the gas phase to solid nitrogen. 相似文献
14.
Sh. M. Khaliullin A. Sh. Khaliullina A. Ya. Neiman 《Russian Journal of Physical Chemistry B, Focus on Physics》2016,10(1):62-68
The magnitude and character of conductivity were studied for Y2(WO4)3 ceramics synthesized by the ceramic (from oxides) and organic-nitrate procedures. Investigation of the dependence \(\sigma \left( {{\alpha _{{o_2}}}} \right)\) and measurements of the ion transport numbers of charge carriers by the EMF method showed that Y2(WO4)3 is basically an ion conductor. The conductivity is largely determined by the sample preparation conditions related to the dependence of the specific surface area and powder grain size on the synthetic procedure. The maximum high-temperature conductivity of Y2(WO4)3 was 2.51 × 10–4 S/cm, which roughly corresponds to the conductivities of Sc2(WO4)3 and In2(WO4)3 measured under the same conditions. It was confirmed that Y2(WO4)3 crystallizes as a mixed monoclinic-orthorhombic structure at 1000°C. The character of water incorporation in hydrated Y2(WO4)3 crystals was studied by thermogravimetry and diffuse reflectance IR spectroscopy. A qualitative model of water intercalation was suggested. 相似文献
15.
Zhaoxia Bi Rong Zhang Weiping Li Xusheng Wang Shulin Gu Bo Shen Yi Shi Zhiguo Liu Youdou Zheng 《中国科学G辑(英文版)》2003,46(1):41-46
With the solid phase reaction between pulsed-laser-deposited (PLD) ZnO film and α-Al2O3 substrate, ZnAl2O4/α-Al2O3 complex substrates were synthesized. X-ray diffraction (XRD) spectra show that as the reaction proceeds, ZnAl2O4 changes from the initial (111)-oriented single crystal to poly-crystal, and then to inadequate (111) orientation. Corresponding
scanning electron microscope (SEM) images indicate that the surface morphology of ZnAl2O4 transforms from uniform islands to stick structures, and then to bulgy-line structures. In addition, XRD spectra present
that ZnAl2O4 prepared at low temperature is unstable at the environment of higher temperature. On the as-obtained ZnAl2O4/α-Al2O3 substrates, GaN films were grown without any nitride buffer using light-radiation heating low-pressure MOCVD (LRH-LP-MOCVD).
XRD spectra indicate that GaN film on this kind of complex substrate changes fromc-axis single crystal to poly-crystal as ZnAl2O4 layer is thickened. For the single crystal GaN, its full width at half maximum (FWHM) of X-ray rocking curve is 0.4°. Results
indicate that islands on thin ZnAl2O4 layer can promote nucleation at initial stage of GaN growth, which leads to the (0001)-oriented GaN film. 相似文献
16.
Tian Yu Tang Sheng Qiang Ren Yuan Liu Jing Quan Zhang Cai Liu Li Li Wu Wen Wu Wang Wei Li Liang Huan Feng 《Russian Journal of Physical Chemistry B, Focus on Physics》2018,12(3):503-509
Zn2SnO4 (ZTO) is a stable semiconductor in ZnO–SnO2 system and important transparent conducting oxide (TCO) predominantly used in optoelectronic devices. ZTO thin films were prepared by RF magnetron sputtering using Zn2SnO4 ceramic target in this paper. The effects of annealing temperatures and oxygen contents on characterization of ZTO thin films were studied. The results show that ZTO thin films prepared by RF magnetron sputtering are amorphous with an optical band gap of 3.22 eV. After annealing at 650°C in Ar atmosphere for 40 min, ZTO films possess a spinel structure with an optical band gap of 3.62 eV. The atomic force microscope (AFM) data of morphology reveals that the surface roughness of films is about 2 nm. The results of energy dispersive spectrometer (EDS) show that the concentration ratio of Zn to Sn is in the range from 1.44 to 1.57. The results of Hall-effect-measurement system reveal that the resistivity of films varies from 102 to 10–1 Ωcm, carrier concentration is about 1017 cm–3, and mobility ranges from 100 to 101 cm2 v–1 s–1. 相似文献
17.
A Li0.5FeV1.5O4 sample was synthesized using sol-gel route. The X-ray diffraction study indicates formation of spinel phase (with Fd3m space group) for this sample. LiO4, LiO6, and V-O bonds were identified from the Raman spectrum, while LiO4 and Fe-O bonds were identified from the FTIR spectrum of this sample phase. The FESEM study indicates formation of inhomogeneous grains. The surface area of 74.39 m2/g was estimated from the Brunauer-Emmett-Teller (BET) surface area analysis technique. The cyclic voltammetry study of Li0.5FeV1.5O4 indicates an anodic peak at 2.1 V while a cathodic peak at 1.98 V. The charge-discharge study exhibits two voltage plateaus respectively at 2.1 and at 4 V. Stable electrochemical capacity of 40 mAh/g for Li0.5FeV1.5O4 was found for 30 cycles. The electrochemical impedance spectroscopy study indicates smaller bulk resistance and higher ionic diffusion, i.e., less Warburg impedance for this phase. An energy density of 89 Wh/kg, a power density of 33 W/kg, and a 90% Coulombic efficiency was achieved with relatively good cyclic stability from Li0.5FeV1.5O4. 相似文献
18.
Polyaniline/Zn0.5Cu0.5Fe2O4 nanocomposite was synthesized by a simple, general and inexpensive in-situ polymerization method in w/o microemulsion. The
effects of polyaniline coating on the magnetic properties of Zn0.5Cu0.5Fe2O4 nanoparticles were investigated. The structural, morphological and magnetic properties of as-prepared samples were characterized
by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectra, scanning electron microscopy (SEM) and magnetic measurements.
The morphology analysis confirmed that polyaniline was deposited on the porous surface of magnetic Zn0.5Cu0.5Fe2O4. It was shown that the saturation magnetization and coercivity of Zn0.5Cu0.5Fe2O4 decreased after polyaniline coating, which can be interpreted by the interparticle dipole–dipole interactions that contributed
to magnetic anisotropy and changed the magnetic properties of the nanoparticles.
PACS 74.25.Ha; 81.05.-t; 81.05.Lg 相似文献
19.
The absorption spectrum of thin K2ZnI4 films has been investigated in the range of 3–6 eV at temperatures from 90 to 340 K. It is established that this compound belongs to direct-gap insulators; low-frequency exciton excitations are localized in the ZnI4 lattice layers and have a quasi-two-dimensional character. The spectral analysis revealed the existence of two K2ZnI4 modifications, which presumably belong to the monoclinic (I) and orthorhombic (II) phases. The temperature dependences of the spectral position and halfwidth of the low-frequency exciton band in K2ZnI4 revealed the existence of first-order phase transitions at 215 and 225 K in the monoclinic and orthorhombic phases, respectively. 相似文献
20.
S.?I.?Pesotski? R.?B.?Lyubovski? M.?V.?Kartsovnik W.?Biberacher N.?D.?Kushch A.?Kobayashi B.?Zhou 《Journal of Experimental and Theoretical Physics》2009,109(4):664-666
The behavior of the de Haas-van Alphen oscillations in the organic quasi-two-dimensional metal α-(BETS)2NH4Hg(SCN)4 is comprehensively studied as a function of the angle between the magnetic-field direction and the normal to the conducting
layers in it. The angular dependence of the oscillation amplitude has minima at angles of ±40° and ±62°, which are caused
by the spin zero effect. The positions of these minima suggest that the electron-phonon and electron-electron interactions
in this metal are significantly weakened. 相似文献